MOSCOW — The spokesman for Ramzan Kadyrov, Chechnya's strongman leader, says his boss will sue a top human rights organization for claiming he was behind the brazen slaying of one of its activists.

Natalya Estemirova, an activist for the group Memorial, had exposed dozens of rights abuses in the Russian region of Chechnya. Her bullet-ridden body was found Wednesday, hours after she was kidnapped by four men not far from her home in the Chechen capital, Grozny.

Oleg Orlov, Memorial's chief, said Thursday: "I know who is guilty of Natalya's murder. His name is Ramzan Kadyrov." Orlov said he meant Kadyrov carried broader responsibility rather than ordering her murder.